Get ready for the whining about how we shouldn't inconvenience people (who want to buy guns with which to shoot other people).

Some say it's a major loophole in the law. At gun stores, you have to get a background check before you can buy a weapon. But online in most states, anyone from law-abiding citizens to dangerous criminals - even terrorists - can get just about any weapon they want, no questions asked. Our hidden camera investigation shows the deals going down in broad daylight, in suburban mall parking lots.